The technical field of this invention is the topical application of personal care agents and, in particular, methods and compositions for the application of fragrant products to the skin.
Application of fragrant skin products (e.g., perfumes and fragrances) to one's skin in order to become more attractive to others, or to enjoy a pleasantly fragrant local environment, is a long-standing practice. A wide range of preparations are available for this purpose, including perfumes, colognes, lotion and powders. The active ingredients in such preparations are typically natural or synthetic organic compounds of low to intermediate volatility; unsaturated esters, ketones and aldehydes are particularly common ingredients. Fragrant products normally contain tens or hundreds of individual components, some of which in pure form have pleasant odors, some unpleasant odors, and some almost no odor at all. Smell is a complex and highly evocative sense whose mastery demands both art and science.
Ideal compositions for use as skin fragrances should be readily portable, spill-resistant, easy and unobtrusive to apply, readily distributable over the skin, invisible on clothing, long lasting, and able to provide an undistorted rendition of the intended fragrance. Most skin fragrance preparations are liquids or powders which do not fully satisfy these requirements. Portable, essentially invisible liquids can readily be compounded to have diverse odor intensities, but they are easily spilled, and they announce their use by a strong odor burst which makes private use in public difficult or impossible. Alternatively, powders tend to be messy, and they can be seen on the skin and are highly visible on clothing. As well, they cannot be compounded with enough active ingredients to produce strong, long-lasting fragrances, and adsorption effects often hamper accurate rendition. There thus exists a need for fragrant skin products which offer a better combination of convenience, privacy of application, invisibility, and accurate, long-lasting rendition.
Details of the formation of cellulosic powders can be found in the above-referenced parent application, U.S. Ser. No. 358,690, filed May 30, 1989, and a commonly-owned, copending application entitled "Process For Producing Liquid-Loaded Powders", by Larry D. Nichols and John F. Cline, Attorney Docket No. MOE-014, filed contemporaneously herewith, both of which are incorporated herein by reference. A preferred liquid-loadable powder includes microporous cellulose triacetate prepared by the method of the above application, Attorney Docket No. MOE-014, entitled "Process For Producing Liquid-Loaded Powders".
In one technique, the liquefiable powders are formed by dissolving a cellulosic polymer and a pore-forming liquid in a volatile, polar solvent (e.g., a low molecular weight halogenated hydrocarbon, ester or diester) and then dispersively evaporating the solution, for example, by spray drying. Suitable volatile solvents for cellulosic polymers include methylene chloride, acetone, ethyl acetate, ethyl carbonate, methyl formate and the like. Methylene chloride is a preferred solvent when the cellulosic polymer is cellulose triacetate. Alternatively, other solvents, such as formic acid or the like, can be used and the resulting solution can be sprayed into a non-solvent such as methanol where the powder particles are then recovered by filtration and rinsing. The active agent can be incorporated into the solvent or introduced by liquid phase substitution after the powder is formed.